Finally found a ~2011 era Cervélo P3C at a bargain price on Ebay - £490 for a fairly pristine frameset, with a lot of dura ace left on it - so the upgrade from my old Dolan Aria (somewhere higher up this thread) has materialised! General consensus seems to be, with the right optimisation, you can get the P3Cs somewhere “close enough” to bikes 5 times the price. It certainly feels very fast…
Currently running USE Tula bars, which don’t offer the current trend to high stack (hence the long stem), but are by all accounts super fast bars (£100 on FB marketplace). Aerolab make highsided alu arm rests for £60, but do basic job as well as the pricey carbon ones.
Gearing is Shimano Dura Ace 55/39 with a waxed chain. The next upgrades will probably by moving to a single ring 58T at the front, and sourcing a TriRig brake for the front. The Zipp wheels are borrowed from my university/“college” cycling club, which means the whole frameset build comes in at well under £1000.